The Effects Of Airbags On Severity Indices For Roadside Objects : Summary Report

007953521998PDFResearch PaperFHWA-RD-98-056Roadside hazardsSingle vehicle accidentsAccident severityAir bagsMeasurementHighway Safety Information Systems (HSIS)Severity Index (SI)Illinois;North Carolina;UtahTurner-Fairbank Highway Research CenterUnited States. Federal Highway AdministrationNTL-SAFETY AND SECURITY-AccidentsNTL-SAFETY AND SECURITY-Highway SafetyNTL-REFERENCES AND DIRECTORIES-StatisticsFederal Highway AdministrationCollisions with roadside objects account for almost one-third of the traffic fatalities in the United States, and a large amount of serious injury and accident costs. A measure of the average severity of these impacts, the Severity Index (SI), is used by highway safety engineers in determining where best to spend roadside improvement funds. Since airbags have been shown to reduce the severity of driver injury in roadside crashes, a question of interest is how an airbag will affect the SI. Such knowledge could be used to refine estimates of the SIs as the vehicle fleet changes to total airbag protection. In an earlier large-scale study of Severity Indices by Council and Stewart, North Carolina data were used to develop preliminary estimates of how the presence of an airbag might affect SIs. Indices were developed for trees, utility poles, and guardrails (faces and ends combined) based on the proportion of serious and fatal driver injury. The data indicated that there is indeed a difference in the proportion of drivers who are seriously injured in cars equipped with airbags vs. those not equipped with airbags in fixed-object collisions. The SI for guardrails showed the greatest decrease due to the airbag, approximately 74 percent; trees and utility poles had decreases of approximately 36 percent and 42 percent, respectively. The results, however, indicated a clear need for a larger sample of airbag-equipped vehicles, a more recent vehicle fleet, and a multi-State data base for validation purposes. This current study was designed in an attempt to meet those needs. Figures; table, 4p